


Caudal

by DumpsterDiving101



Category: Phandom/The Fantastic Foursome (YouTube RPF)
Genre: AU, Cave, Fantasy, Gen, M/M, Mind Control, Mythology - Freeform, Sharks, Siren, Stranded, caudal, fins, knife, mermaid, merman, powers, stuck
Language: English
Status: Completed
Published: 2017-12-21
Updated: 2017-12-21
Packaged: 2019-02-18 05:24:16
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,426
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13093305
Author URL: https://archiveofourown.org/users/DumpsterDiving101/pseuds/DumpsterDiving101
Summary: Summary: The cave has two exits. One, a hole in the ceiling, wide enough that Phil could see the stars glitter at night. The other exit was through the pool in the middle of the cave, where they’d come from.The siren leaned against the cave wall a few meters away, tending to his wound. It wasn’t bleeding anymore, but the damage was done. Sharks circled in the pool, desperate for a taste of the merman.The hole in the ceiling was too high up, the walls too steep to climb. The sharks circled in the pool of water, ready to eat whatever comes their way. No way out. Phil was stuck, with no food, no fresh water, no hope to escape, and a siren who had tried to drown him not hours before.Themes: merman/mermaid/siren!au, sharks, survival, enemies to ?





	Caudal

**Author's Note:**

> Check out the art for this fic [here](https://dansphlevels.tumblr.com/post/168614421728/mermaids-please-i-love-mermaids)!

Phil was not supposed to be there. 

 A storm was coming. The waves lapped against the coastal sand, hitting it harder than it had the day before. The sky was more gray than blue and more cloudy than clear. The gray had infected the water, turning it darker. Even before the first raindrops fell it was clear that a storm was on its way. 

 So all in all, the beach was not a good place to be. But Phil found himself walking along the sand, his bare feet no longer complaining after all the time he’d spent on that very beach that month. A change of scenery was good for people whose minds were blocked, so he’d heard. So far, the retreat was more of a break from reality, and though no new ideas came to his mind, it was a much-appreciated one. 

 He allowed himself to walk right up to the edge of the sea, letting the waves pound at his legs. They weren’t too big, just forceful, as if pushing him back. 

 The wind blew hard against him as if agreeing. It whipped against his white t-shirt and tan cargo pants, blowing his raven hair back. He wasn’t in swimming trunks, but it hardly mattered. No phone- it had been left in Manchester, very purposefully- and no wallet- no need for one, his rental house wasn’t far away. Really, no reason why he shouldn’t go for a quick dip. 

 He took a few steps forward, and all around him it grew quieter. The birds calmed, the wind dyed down, even the water seemed to be less harsh. 

 He took another step forward, and heard a strange sound, something that didn’t in any way belong in the ocean. It was… a piano? 

 Phil’s feet walked forwards on their own free will, diagonal along the coast towards the rock formations a half kilometer away. They were shaped like mountains but much, much smaller, only a short hike to the top. Phil had wondered why no one ever came to this beach, and over the past few days being here he’d decided it must be because of the intrusive rock formations. They were ugly, and there were lots of things like that under the water when you got over too far. Bad for surfing, and no good for pictures. The beach was completely deserted, every day of the week, even when it didn’t storm.

 These thoughts went through Phil’s mind as he walked, the gentle playing of the piano becoming less faint as he grew closer. Soon, he was up to his waist in water and started swimming, doing a smooth front stroke towards the noise. The ocean stilled for him, as if it was listening to the playing as well. 

 He swam out further than he planned to, but there wasn’t a single thought in his mind that made him want to turn back. He had to find out where the noise was coming from. It was a beautiful tune, unlike anything he’d ever heard before. The notes ran together easily, enticing and beautiful and perfect. Whoever was playing the instrument must have a true passion for it, and a talent as well. 

 There were large outcroppings of rocks sticking out of the water that Phil had to swim around. He slid in between them, careful to keep his legs from touching the sharp, dark grey stones on either side. The area was badly polluted, with soda cans and plastic bags floating in the water. A fisherman’s net slid against his legs, catching on his foot. Phil had to pull out his pocket knife and cut it. The pocket knife was for opening clams, but luckily, it worked, and Phil was free from the ropes. 

 Phil began to swim faster as the source of music came closer. The piano keys tapped delicately one after another, going in his ears and circulating through his entire body. Every cell, every tissue yearned to go closer, begged to find the source. It was The Answer, to everything he’d wanted and everything he was searching for. This was why he was here, this was the reason he was  _alive_. 

 A rowboat was wrecked against one of the huge slabs of rocks. A large chunk had been taken out of it by a mouth the size of Phil’s torso. He kept swimming, faster. He had to get to the noise, he had to get to the music. 

 He swam past the last rock outcropping, into the open sea. The music pulsed and hummed, all around him, but when he turned in a full circle he saw nothing, no piano anywhere. But it was here, he knew that with all his being and all his mind, it was here. 

 He held his breath, and dived under, opening his eyes underwater. He looked around desperately, his actions becoming more and more anxious. Where was it? He had to find it, this was The Answer! He needed The Answer! 

 The water was so deep he couldn’t see the bottom. Nearby, there was a huge wall of rocks, sharpened and deadly, part of the mountains that made this bay so ugly. But where was the music? Where was it?!

 Phil came back up, gasping for air. It had begun to rain, droplets of water hitting the sea in little ripples of motion.

He treaded water, catching his breath, his heart pounding in his ears as he realized the music had stopped. Not a bird dared to chirp, nor the waves dare to splash. Everything was perfectly silent.

 Something wrapped around his leg and Phil had no time to scream as he was ripped into the water. Someone had grabbed him, and Phil yanked and tried to kick or pull away or do something but whatever it was had grabbed ahold of him and wasn’t letting go. Bubbles raced to the surface as they descended so quickly Phil’s ears popped and he heard the thumping of a drum in his head. 

 Something had grabbed him, a slick form that felt almost like a human hand, wrapping around his ankle tightly, pulling him down. And he was going to die. 

 The thought made his brain go into overdrive, it’s blurry waterlogged HTML code sending mass orders of panic.  _Get away get away get away get away_  was blared through loudspeakers on repeat, his entire body screaming in terror and agony as they descended so rapidly the pressure made his insides crumple like a soda can. 

 And then they were slowing, the decent smoother. This was the moment before the white of death, where everything slowed as your heart prepared to stop. Phil’s arms went down to his sides, working on orders from the shred of his brain that still worked. He fumbled with his pockets. 

 Phil looked down and almost blacked out. 

 The tail was the color of crystalline swamps, a shade of green unlike anything Phil had ever seen. Fins ran off of it, flowing naturally in the dark water. A hand, a human hand the color of milk but slightly sickly green was wrapped around his ankle, pulling him down. The figure, the monster, the mermaid, the whatever it was, pulled him deeper. A creature of terror, of darkness, of death, it swam downwards towards the ocean floor and Phil’s immediate death.

 The tail brushed against his legs. 

 Phil pulled out the object from his pocket and opened it. Before he had time to consider it, he plunged the knife into the creature’s tail.

 Horrible dark blue liquid the color of poison poured out from the wound, and the creature let go in pain, it’s body writhing with agony. For the first time, Phil saw its face, human, a boy’s face twisted in pain and horrible anger, pointed teeth bared and ready to rip his throat out as Phil tried desperately to swim away. It swam to him in a burst of motion, grabbing him and pulling him down, when something changed and it shoved him away. The water was turning sickly blue from the blood, and the creature was looking at something in the distance. Then he turned, swimming away at an incredible speed away from whatever was there, and Phil may have been drowning but he knew danger when he saw it. He followed, hurriedly, kicking with all his might and praying that he wouldn’t drown. His lungs begged to burst, his whole body screaming in pain at the pressure. 

 The mermaid swam into one of the caves formed by the rocks, and Phil followed, desperately kicking and praying and drowning all at once because he was a talented individual who refused to die like this. 

 The light of day was getting closer, and he swam upwards, letting out his final puff of breath and begging the God he didn’t believe in to save him. 

 And then there was light, and then there was air, and Phil gasped and swam to the edge of the pool, trembling hands gripping onto rock. He didn’t know what was chasing them, but he knew that if it was bad enough to scare the merman, then he didn’t want to meet it. 

 Phil dragged himself onto land, coughing and then vomiting, the taste of salt wedged underneath his tongue and down his vocal cords. He crawled away from the pool of water, his entire body shaking with cold/fear/exertion/pain. 

 Nothing came out of the water to kill him. He was safe, for now. 

 Phil had finally stopped throwing up and managed to slump to the ground a few feet away, his entire body aching horribly.

 "Hello there. I’m sorry I didn’t drown you, this would have been much easier for the both of us if you’d just died like you were supposed to.“

—

 Phil sat against the stone wall of the cave, his feet resting on the sandy ground. 

 Across from him, on the other side of the pool, lay the creature. He was… well, Phil knew what he was. But he wasn’t sure if he could admit it. 

 The creature’s top half was almost human. He had a male torso, and though he had muscles, he also seemed skinny to the point of malnutrition. His skin was extremely pale, with an almost green tint. If you looked at his face and just his face, you might call him handsome, but possibly ill. Damp brown curls hung over his eyes, and he pushed them back in annoyance.

 Phil wished that was all. But it wasn’t. 

 Under his belly button, where one’s stomach would begin to curve into a pelvis, the skin turned scaly. Instead of having legs, he had one massive tail, long and dark, swampy green and onyx black. 

 "You’re a mermaid,” Phil said aloud, still staring at the boy. 

 He huffed. “I’m not.” His voice croaked, and he cleared his throat, the same way Phil had to do whenever he hadn’t been using his voice for a while. 

 "Then what are you?“

 The creature- the man- the not mermaid?- sat up a little straighter, showing off his pale green inner arms. A small smile tugged at his lips. “Come on, you know. I was the one who grabbed you. You don’t look horribly dumb, just make a guess.” 

 "You’re a merman,“ Phil suggested, his voice monotone. His eyes flickered back and forth between the creature’s tail and his eyes. Dark, very very dark, probably brown. 

 He rolled his eyes. “I’m not a mermaid, or a merman, or whatever else you’re suggesting. Mermaids don’t exist anywhere but German fairytales and old pirates stories. And in case you haven’t noticed, I exist.” 

  _I noticed_. “Then what are you?” 

 He smiled again, like he was imagining trying to drown Phil and succeeding. “Well, I’m a siren, obviously. You heard my music.”

 The puzzle pieces clicked together all too late. “The piano music.” 

 "That was me,“ he agreed. “I always think, surely this time they won’t fall for it. Someone will have enough sense not to go out to sea in search of a piano of all things. And every time, I’m mistaken.” He shrugged, and the end of his tail, the semi-transparent parts flapped nervously.

 Phil looked into the water. The cave was about the size of a small room, circular, with most of the space being taken up by the pool in which they’d small up in. Above, it rose in the shape of a mountain, with a giant crater at the top where they could see the gray sky through. 

 The water lapped at the constraints of the pool upsettingly, dark and blue without any green at all. Far below, Phil could see something move. 

 "Something’s-“

 "Sharks,” the siren supplied. “They love the taste of sirens. Can smell our blood from miles away, and come racing.” He crinkled his nose in annoyance. “Rude of you to stab me. It will take at least two or three days to heal, and who knows how long the sharks will stick around for.”

 "Sharks,“ Phil repeated, still staring down into the murky depths, trying to make out any features. 

 "Yes,” the siren agreed, as if talking to a small child. 

 "And you’re a siren. Which is different from a mermaid, apparently.“ 

 "Yes.” Now he looked slightly annoyed. Phil wondered if he’d try to drown him again. “Mermaids are fictional. And sirens…”

 "…play piano music in the middle of the bay,“ Phil finished. “And are attractive snacks for sharks.” 

 He was definitely going to drown Phil. 

 "You act as if I’m the bad one. Like, out of the three of us in this cave, I’m the worst one.“ 

 "Three of us?”

 "Including the shark. Though there’s likely more than one. I can see better if I stick my head underwater, but right now my goal is not to die, so I’m not going to do that.“ 

 Phil backed up from the pool, going back to his original position against the cave. He bent his knees, bringing them to his chest. "Yeah, but you’re the one who tried to drown me. That’s pretty bad in my books.” 

 "You’re the one that tried to drown me,“ he corrected. "With carbon emissions and pollution. Honestly, have you ever thought about your actions? That maybe dumping thousands of tons of sewage into the ocean each year might be a bad idea? Because I have some news for you, some of us have to live in that ocean, and we can’t do that very well when you’re destroying our ecosystems!”

 Phil blinked. 

 Dan stared back at him, not daring to look away. 

 "Nerd.“ 

 "Oh my god. Oh my god. Wait ‘til I get my hands on you, you slimy little land bastard-” 

 "I prefer Phil, actually.“ Phil smiled, tilting his head a little. His skull ached, like someone was trying to hammer new information into it. Maybe he was seeing things. After all, he did just inhale a lot of seawater. 

 Neither spoke for a while. Eventually, the siren stopped staring at Phil and instead tended to his injury. 

 Phil tried to mind his own business for a few minutes, observing the cave. He doubted the merman siren could get out by a land exit, but he probably could. He looked around, and then eventually stood, walking around his side of the cave. He was able to walk all the way over to where the siren lay without any difficulty, but he’d already almost died once today. The last thing he wanted was to be thrown to the sharks while being lectured about carbon emissions. 

 Every once in awhile, Phil caught the siren looking at him. Whenever he caught Phil’s eye he would quickly look away, back to his wound. 

 Finally, Phil decided he had to accept it. There were only two exits to the cave: the pool and the hole in the roof. Unfortunately, the pool contained a shark hungry for a fish-human hybrid, and Phil didn’t doubt that he’d settle for just a human. And the walls were tilted towards the hole in the ceiling, making them impossible to climb. It was like the inside of a volcano, Phil realized, but with a pool of water instead of magma. 

 He tried to be discrete about looking at his company in the cave. But as he watched him work, he realized something. 

 "You took the knife out?” He asked before he could stop himself. 

 The siren huffed, pushing his brown curls away from his face in annoyance. “Clearly.” 

 "You should have kept it in. It was the only thing keeping your blood from flowing out, you’re supposed to leave it in until you get to a vet.“ 

 The creature looked up so pointedly Phil wondered if he should make things easier and just jump in the water on his own terms. "A…. vet?” 

 "You know, like a person who cares for animals.“ 

 "I know what a vet is,” he snapped. “But I’m offended that you’d suggest I might need one.” 

 Phil blinked. “I mean… you’re tail…” 

 He brushed it aside. “You know what, never mind. It doesn’t matter anyway, because I took the knife out already. In the water. That’s why I bled so much, that’s why the sharks came, and that’s why we’re in this mess.” 

 "Because you took the knife out?“

 "Because you stabbed me.”

 Phil huffed. This wasn’t getting anywhere.  

 "How’d you know that anyway? The knife thing?“ 

 Phil crossed his arms, looking down at the surface of the water, turned gray from the sky’s reflection. "I went to school to be a vet. I ended up doing something else, but I still ended up learning a lot of stuff like that.” 

 He stared at the sand, digging in it with his fingers. It was true. He’d ended up changing to studying language and film after he’d gone to see surgery performed on a horse and passed out. 

 He was so deep in thought he hadn’t even realized the siren was saying something. “Feel…. Feel! Erm, Fell? Feel? Phil!” He snapped, and Phil looked up. “Phil!” 

 "What?“ 

 "Stop digging around and come help me! God, you’re a vet, I’m not supposed to have to ask.” 

 Phil stood, looking at him unsure. “Will you drown me?” 

 "Not until after you help me.“ 

 "No.” He crossed his arms tightly, hoping the merman couldn’t see how nervous he was. “Promise you won’t try to kill me. At all. Ever.” 

 He whined. “But _Feeeeeellll._ ”

 "It’s Phil.“ 

 "But _Phiiiiiiiiillllllll_.”

 "Do you want help or not?“ 

 He pouted. "Fine.” 

 "Swear it. On your tail,“ Phil added quickly.

 He continued to pout, but gave in. "I swear on my tail that I won’t try and kill you again if you heal me.” 

 "If I help you,“ Phil corrected. "I’ll do my best, but I have no supplies.” 

 He groaned. Phil decided it was enough and walked over and knelt next to him.

The wound probably looked worse than it actually was. Even so, it didn’t look too bad. “Well, you’re not bleeding much.” 

 "Wow, thanks for that professional advice.“ 

 Phil ignored him. "Does this hurt?” He reached over, carefully touching the area around the wound. It was a little darker blue-green than the area around it. Phil realized too late that it was stained with the siren’s blood. 

 “It doesn’t really hurt,” he announced.

 Phil nodded. "That’s good. Um… you should… apply pressure.” 

 "Great.“ He seemed unamused but did so anyway. 

 Phil’s mouth tasted like seawater. He was on one knee next to the creature, right next to his tail. It was even more beautiful up close. So dark green it was almost black. Now that Phil was closer, he could see flicks of gold in it, especially around the area where the tail met with his skin. 

 "You’re staring,” the siren noted. 

 "Sorry.” Phil tried to stand, but his eyes caught onto the fins at the very end of the tail, lighter greens and blues with golden veins. "Can I touch it?” 

 "Um, what?” 

 "Touch your… fins. The flipper things.” Phil pointed. His tongue seemed to have forgotten how to work.

 "My… caudal fins? Fine, just be very gentle. They tear easily.“ 

 Phil crawled over and knelt next to the flippers. Most mermaid pictures and drawings he’d seen depicted the end of the tail, where a human’s feet would be, to be two elongated flippers, like those ones that some freedivers used. Or maybe it was one flipper, shaped like a v. 

 The siren’s ‘caudal fins’ were not like that. It was as if he had multiple pairs of mermaid fins all stacked on top of each other.  Smooth and soft like fabric, folded together in a confusing mess. 

 Phil reached out, and touched it. All of sudden the fins shot out, jumping and unfolding to form one massive flipper in the shape of a math bracket {. 

 It unfolded so fast and took up so much room that Phil was almost pushed into the pool of water. 

 His eyes widened. "Woah.” 

 It was clear the siren wasn’t sure what to think. He had a perfect poker face, like he was just observing Phil, trying to decide what to make of him. 

 There was a rip in his tail, a little hole by the ends, which were a little torn themselves. “What’s this from?” 

 "Fishhook. Like I said, you humans have no respect for the creatures of the sea.“ 

 He folded his tail once more, pulling what would have been his knees up to his chest and leaning on it. "Okay, now it’s my turn. Come here.” 

 Phil gave him a strange look but crawled over anyways. 

 "Let me see your… legs. That’s the word. And your… feet? Those.“ 

 Phil hesitated. "Wait. I need to know your name first.” 

 "Why would you need to know that?“

 "I don’t like strangers touching me. Just a general rule.” 

 The siren stared at him intently. “Fine. My name is Danye.” He pronounced it like ‘dawn-yay’. “But you can call me Dan, since humans lack vocal ability. My pronouns are he/him.”

 Phil looked up. “I’d kind of assumed that already.” 

 "Rude. You should never assume someone’s gender.“ 

 "I mean- I wouldn’t think that mer- sirens would care about that sort of thing.” 

 Dan gave him a look like he wasn’t sure how much to tell him. Then he shrugged. “Meh. You’ll probably die in the next few days anyways. You would care a lot more about pronouns if none of the creatures of your species had penises.” 

 Phil found his eyes drifting down to Dan’s waist. “Um… you don’t-” 

 "Have a dick? Oh yeah, sure, let me pull my tail down like a pair of pants. It’s around here somewhere… Obviously not, you  _fern_. And don’t ask how we reproduce, because I’m not going to tell you.“ Dan patted the spot next to him. "Come here.” 

 Phil decided to just listen, scooting over. Dan quickly grabbed his ankles, dragging him a little closer. “Your legs are filthy,” he noted. 

 "What? No, that’s just hair.“ 

 Dan looked at him like he was trying to decide if he was lying. "You grow hair out of your legs?”

 "Um, yeah? And out of our arms, and chests, and stuff. And most guys my age can grow beards, if they try. I can only get a weird neck beard.“

 Dan touched his neck, as if imagining hair sprouting out from it. As he moved his arm, Phil realized his armpits were completely bare of hair.

 Eventually, Dan went back to inspecting his legs. Apparently, he’d known what toes were but never realized there was such thing as toenails. He prodded at Phil’s ankle bones and felt his knees. "It’s unnatural,” he decided finally. “And frankly, I’m uncomfortable.” 

 "Hey! You’re the one who’s part fish!“ 

 "And you’re the one sitting by the shark-water, so I’d watch it,” Dan threatened. “Can you see them?” 

 Phil leaned over, looking into the water. A figure circled beneath, closer than it had before. “Only one, I think.” 

 Dan rolled over onto his stomach, a real process with his large tail. He dragged himself over to the pool by his forearms, army crawling close enough to see over it. 

 "How long until it leaves?“ 

 Dan shook his head. "A few days, at least. Sharks will do just about anything for a taste of sirens.”

 Phil’s stomach ached. “What do we do?” 

 "Wait it out.“ His voice was calm, which would have been reassuring if he didn’t look so worried. 

—-

 The rest of the day was spent waiting. They were shaded from the sun, but it still came in from the cave, glittering against the water. 

 Phil retreated back to his side of the cave and laid on his back, staring up at the walls curving up to the hole in the ceiling. The walls weren’t smooth, but he doubted he could climb out that way. It would take upper body strength that he just didn’t have.

 He didn’t dare nap. It might be difficult for the merman to crawl over across the sand, but Phil didn’t doubt that he could. And, as casual as their interaction earlier was, this was still the creature that had tried to drown him. Phil knew better than to trust the creature too easily. 

 At some point in the afternoon, Phil rolled over onto his side and found Dan laying on his side as well, staring at him from across the water. When he caught his gaze, Dan scowled and rolled over, staring at the wall. 

 Phil watched the sharp edges of his back, observing the dark contours and the greenish tint of it. Then, lower, as the skin turned into thick green-black scales that lead to his tail, longer than human legs, with the folded caudal flipper at the end. He moved his flipper around nervously, tapping it against the sandy ground. At one point, his fin twitched, launching a pile of sand into the water so aggressively Phil wondered how strong his tail was. It must have been incredibly powerful. He remembered the hands wrapping around his feet and the force pulling him down so quickly there was hardly any resisting it. Dan had been able to do that with hardly any exertion. 

 His stomach ached slightly as the day went on. He would have been okay if he hadn’t thrown up his breakfast- a painful side effect of almost drowning. 

 Phil kept thinking that they’d start talking again, but the siren seemed intent with ignoring him. Finally, the long day was over and Phil could feel his eyelids weighing down, begging to be closed. He wanted sleep. After a short struggle, he gave in, hoping that he’d wake up in the morning. 

—-

 Dan did not kill him. 

 When Phil woke up, Dan was leaning over the pool, staring into it. He glanced up when he heard Phil stir, then went back to looking into the water. 

 "There’s more,” Dan noted. 

 It took Phil a few moments to process. “More what?” 

 "Sharks. I see at least two, but I think there’s a third one.“ 

 Phil could feel his stomach rumble. "What do we do?”

 "Wait it out.” 

 "How long?” 

 "As long as we need to,“ Dan snapped. "Unless you want to jump into the pool and try swimming.”

 "Would it work?“

 "No. You humans are miserable swimmers, you’re painfully slow, what with your deformed fins. They’re horrible for propelling you.” 

 Phil took a wild guess that Dan was talking about his feet. “We don’t have fins. They aren’t deformed, they just are made for land use. I can swim better than you can walk.” 

 "You want to test that theory?” Dan gestured to the shark-infested pool. "Be my guest.” 

 Phil stood slowly, brushing the sand off of his clothes. “If you’re so intent on me dying, why didn’t you just kill me in my sleep? You could have tossed me to the sharks and been done with it.” 

 The siren looked more hesitant now that Phil was standing. He had to look up to see him.

 "I didn’t throw you to the sharks,“ he explained slowly, "because then they’d win. I  _hate_  sharks. Even more than I hate humans. If I kill you, trust me, I’m not going to let the sharks get something out of it.” 

 That did not reassure Phil. “But you wouldn’t kill me anyway,” he reasoned. “Because we made the deal.” 

 "I agreed not to kill you if you healed me. Well, guess what.” Dan moved a little ways back from the water, bringing his tail around for Phil to see. He pointed at the gash, which appeared to have scarred over, but was definitely not healed. “You didn’t heal me.” 

 Phil ran his fingers through his fringe, brushing the sand out of it. “Healing takes time. What did you expect, that I’d just say the word and it’d be fixed?” 

 Dan looked at the ground.

 Phil realized too slowly. “You actually thought that?” 

 "You humans are insufferable,“ Dan defended. "Too busy polluting the ocean to explore it. There are things down there that would make you curl up in a ball and cry, Phil. Don’t act like you know my world.” 

 "Wait- what? There’s something down there that could heal wounds that quickly?”

 "Shut up.” Dan pulled his tail back behind him protectively, slumping onto his stomach. “It’ll be at least two more days until the sharks go.” 

 Phil’s stomach flipped inside out. “What?”

 "The sharks. They know they have me trapped.” He shrugged. "We just have to wait it out.” 

 Phil could feel his breath quicken as panic set in. “I can’t… I can’t survive that long! I need food-” 

 "You can’t go a few days without food? Wimp.“

 "But I definitely need water. A human can only survive two, maybe three days without water, and even then they might go mad.”

 Dan looked at Phil like he was trying to decide if he was lying or not. “There’s water right here.” 

 "Freshwater! I can’t drink salt water!“ 

 Dan’s voice mimicked Phils, getting higher and louder. "Why not?” 

 "Because- ugh! Because humans can’t process salt! It’ll be worse than drinking nothing because the salt will dry up all the water!“ 

 "What the fuck is wrong with you? Why did you humans evolve to not be able to drink salt water?” 

 "Stop acting like you’re the normal ones! Why would anyone want to drink salt water?“ 

 Phil hadn’t realized, but he’d been stepping forwards, getting closer to the siren. He saw Dan’s eyes widened, then he lashed out, pulling himself up and whipping his tail around, knocking Phil off of his feet. Phil yelped as he collapsed. 

 Apparently, Dan could move fast on land when he wanted to. Within a moment he was on top of Phil, grappling with him and trying to pin him down. 

 Phil tried to slide out from under him, fighting and slapping his hands away. Dan’s tail was extremely heavy, even heavier than he’d previously thought. 

 Dan grabbed something off to his side, and raised it above his head, preparing to strike. Phil processed it in a split second- the gleam of the blade, the way it was still stained from dark blue blood- and before he knew what he was doing, he’d knocked it out of Dan’s hand. It fell into the pool with a plop.

 Dan jumped off of him, reaching out to the water desperately. "That was our only weapon.” 

 Phil sat up, moving away from the siren in a hurry. “Yeah, well you should’ve have tried to stab me!” 

 "You shouldn’t have been preparing to attack me!”

 "I wasn’t!” 

 "Oh really?“ Dan mocked him, squaring his shoulders and sitting up straighter. "You stood up, made yourself look tall and then stalked towards me. If that’s not preparing for an attack, I don’t know what is!” 

 "I was just arguing with you! I wasn’t going to attack you!“ 

 Dan’s tail fin fanned out fully, unfolding into a huge fan. He cursed in a language Phil didn’t recognize, and quickly retracted them. "It doesn’t matter. What is done is done.” 

 He rolled over onto his back, still scowling. “You humans. You’re always right, aren’t you?” 

 Phil was careful to sit down, not wanting to make the same mistake as last time. “What do you have against humans?” 

 “Everything. Do you even know how much of a global footprint you leave? You’re killing our earth.“ 

 “Well, you’re… you’re… you’re over hunting the fish!” Phil retorted. In reality, he hadn’t known sirens even existed until the day prior, much less how they affected the environment. But based off of the offended expression Dan made, he’d hit a sore spot.

 “For your information, we work very hard to conserve our species diversity. The Tecopa fish extinction was an accident! Things like that can’t always be avoided!” 

 “Excuses excuses.”

 “Don’t act all innocent, we may have caused the extinction of Tecopa, but your species killed the Dodo bird! Do you know how upset I was when I found that out?” 

 “The dodo bird has been dead for centuries!”

 “How long do you think it took me to figure that out?“ 

 Phil paused, his eyes growing wide. “How old  _are_ you?” 

 Dan gnawed on his bottom lip. The longer he hesitated, the more Phil freaked out. Could he actually have been alive when the dodo bird was around? Was he a hundred years old?  _Two_ hundred?

 “I’m twenty-five.“ 

 “Oh.”

 “Do I look old to you?“ 

 “No! You look… young, in fact.”

 “Young?“ 

 “Good! You look- good, like, not little or anything-” 

 “Are you calling me fat?“ 

 Phil covered his face with his hands. Dan didn’t say anything for a few moments, then scooted over, the sound of his tail dragging on sand obvious and entirely without grace. 

 Dan tapped on his arm. "Phil!” He whispered urgently. He still pronounced it sort of wrong, like he was trying to say  _Feel_. “It was supposed to be a joke! I forgot how delicate humans are!” 

 "Oh, shut up.“ Phil moved his hands away from his face, smiling at the ground beside him. 

 Dan poked at his arm again, equally urgently. "How old are you?” 

 Phil brushed aside his fringe, looking at the boy’s troublemaker face. “Twenty-nine. Almost thirty.” 

 "How long do humans tend to live?“ 

 "You know about ecological footprints but you don’t have how long humans live?” 

 Dan shook his head. 

 "Guess.“ 

 "Um… Forty years.” 

 "Higher.“

 "Four-hundred years.”

 "Lower.“ 

 "Two hundred?”

 "Usually around seventy,“ Phil supplied, "But it depends. My grandpa lived to ninety-three. How long do sirens usually live?” 

 Dan shrugged. “I don’t actually really know. No one really dies of natural causes, it usually because of predators or fishing nets, that sort of thing.”

 Phil licked his lips. They were beginning to crack. He needed water soon. “That’s… pretty sad, actually.” 

 He shrugged again. “Depends on how you look at it. On the bright side, no one ever really grows old. You’re as strong as you are strong for, and survive as long as you can survive for. Then, when you aren’t strong enough anymore… nature takes its course.” He was playing with a shell in the sand, digging in it absently. “How many sharks?” 

 Phil peered over. “Three. They’re closer to the surface now.” He leaned down a bit more. “They’re a lot closer, actually. And… I think there’s more underneath.” 

 "That’s weird. There’s no reason for-“ Dan stopped mid-sentence, his face going even paler, if that was possible. "Oh no. The knife. Did it have any of my blood on it still?” 

 Phil’s eyes widened. “Yeah. But there was just a little-” 

 "That’s all they need,“ Dan mourned. "They know I’m here, and they’ll be desperate for a taste. No way they’re leaving anytime soon now.” 

 Phil’s stomach turned over. His mouth tasted like salt water and sandpaper. “How long?”

 "Dunno. But we might have to find another way out.“ 

 In perfect unison, they both looked up at the hole in the cave ceiling.

—-

 It was the next day. Phil felt faint and light-headed, and his stomach and head ached. 

 They talked quietly. Every so often, a fin would break the surface of the water. The shark would swim a few slow laps, testing it out, and then submerge once more. Every time one came that far up, their conversation paused, and didn’t resume until it disappeared again. 

 Meanwhile, Dan tried to convince Phil to climb the cave walls. "It’s our only option!” 

 "Dan, do you see them? There’s no way I’ll be able to without falling in!” 

 Dan huffed, his caudal fin bouncing up and down in agitation. It was partially unfolded, maybe half of its full size, and every once in awhile it twitched, closing and opening like the shutter of a camera. Though he didn’t complain, Phil knew Dan was suffering the effects of hunger as well. He was incredibly skinny, only muscle and bones. Maybe he stored fat in his tail, energy to use for later. 

 If they were stuck in the cave for much longed, Dan would survive for more time than Phil would. He wasn’t suffering from dehydration; he still could drink the ocean water, while Phil knew better. He couldn’t filter out the salt like the siren could, it would just make everything so much worse. 

 They stopped arguing as a shark’s dorsal fin peaked through the water. Phil could see its full body through the thin layer of water; it was probably almost as long as he was, and much wider. And there were even bigger ones lower, ones that couldn’t fit in the little pool easily and had to wait further down. 

 It’s fin submerged, and they continued. "It’s our only chance,” Dan argued. “If we stay here, we’ll die. If we try to swim out, we’ll definitely die. You especially, with your deformed…. foot things. This is the only chance we have.” 

 Phil stared up at the ceiling, at least a dozen meters up. “What good would it do you? It’s not like you could get out that way.” 

 "True,“ Dan agreed, "But you could give me provisions. Lower them down. Food, maybe a weapon. Trust me, I don’t like the odds much either, but it’s our best bet.” 

 "I won’t. I can’t do it Dan, I can’t…. what’s that noise?“

 Dan tried for a blank expression. "What noise?” 

 Phil was looking around, desperate to find it. “Its…. it’s music! Don’t you hear it? It’s… a piano!” 

 Dan shrugged, not saying anything. His fingers tapped out a gentle melody against the sand, and he watched as Phil’s eyes widened, and then looked up. 

 "It’s coming from up there,“ he realized. "I have to find it.” 

 His hands were already on the rocks, searching for hand holds. He soon pulled himself up, his feet finding holds. 

 He climbed slowly towards the source of music, getting increasingly frustrated the longer it took. “I have to find it…” 

 Meanwhile, the sharks grew more agitated. They churned, going up to the surface and dipping back down. Two sharks circled, tail to tail, and Dan scooted away from the water, his breathing increasing. His fingers didn’t stop tapping, tapping so lightly he was hardly touching the sand. 

 Phil grunted. His hands were shaking slightly, whether from the stress of not being with the noise or the exertion it wasn’t know. Possibly- likely- both. 

 He was so high that the cave walls had sloped over the pool. If he were to fall, he’d fall into the shark-infested waters. 

 Dan began humming, a low and quiet melody that went along with the gentle tapping of piano keys. Phil cried out, grabbing for another ledge, only centimeters deep. He forcibly pulled himself up. He was only holding on out of pure willpower. 

 _Dan’s_  willpower, to be exact.  

 Over the courage of a few long, painful minutes, Phil managed to climb the increasingly steep cave walls. At the top, it was too smooth for him to find a single handhold, so he jumped. Dan caught his breath as he leaped, pushing up and away from the wall, hands reaching out frantically for the edge of the crater. 

 He grabbed it, swinging as he gripped onto it with both hands, trying to pull himself up. Dan exhaled, “You’ve got this!” 

 But he realized too late. Dan’s fingers were idle, and the music was replaced with an eerie, ringing silence. 

 Phil’s eyes snapped open, like they’d been closed the whole time. His grip loosened, and he dropped like a stone into the frothing water. 

—-

 It happened too fast for Dan to have time to make a decision. He had to go with his gut, and before Phil had even completely hit the water Dan’s gut was throwing himself over the edge into the water. He grabbed Phil and swam. 

 The sharks were so surprised that for a split second, maybe a fourth of a second, they didn’t react. Then they pounced. 

 But by then, Dan was already at the bottom of the pool, swimming with all his might and tearing out of the cave and into the open ocean. He didn’t dare look back, but knew that the sharks were right on his tail- literally. 

 Phil was limp in his grasp, his legs bumping against Dan’s tail with every beat of it. Dan could feel Phil’s heart beating through his tshirt- or maybe that was his own heartbeat,  _thumpthumpthumping_  in his head. 

 He risked glancing behind him as a shark opened its huge maw, ready to snap. Dan dove to the side, barely avoiding having his flipper bitten off entirely. His caudal fin was completely unfolded, beating against the water as his body gyrated rapidly, swimming so fast he could hardly breathe. 

 Another sharp snapped at him, and he dove to the side, narrowly slipping in between two outcroppings of rocks. The waters were becoming more and more dangerous, floating with pollution. Huge outcroppings of rock jutted out from beneath the seafloor, and Dan swam in between them, his entire body made for this type of swimming. Still, the sharks gained. He only had a little time before he made a wrong move and then it was over- for both him and the limp boy in his arms. 

 Dan ducked under a piece of sinking wreckage, weaving in and out of the huge rock formations so fast that his tail whipped against one of them, stinging with pain. 

 Phil was so limp in his arms that he wondered if the boy was even still alive. Then Dan cursed- he’d forgotten humans couldn’t breathe underwater! How long did he have? Surely, Phil could survive another few minutes, right?

 A shark grabbed part of his tail, and Dan wanted to scream as a section of his caudal fin was ripped off, tearing like tissue paper. He swam faster, looking for anything, anywhere he could go to ditch them… 

 He spotted it. It was too far up, but he’d have to make it work. With a ginormous shark right on his tail, Dan dove to the bottom of the sea. At the very last moment, he arched his back and curved, swimming upwards with more force than he’d ever used in his entire life. 

 They broke the surface of the water with so much speed they soared upwards, then fell to the earth and landed on an outcropping of grassy land with a horrible thump. Dan felt Phil slip from his hands, and without any way to stop himself, tumbled a few meters down a grassy hill, sputtering and grunting as his body pounded against the ground. 

 Finally, he came to a stop as they land flattened out. He slowly did one last roll, then managed to groan and stop himself on his back. The sun was so bright it was almost blinding; the sky was so blue it was as if it was trying to imitate the sea. 

 Dan coughed, sitting up. He flexed his caudal fin, slowly extending it to its full length. He’d only lost a small section. It left the end of his fin torn and ripped at, but he knew it would still work, and since it was his fin instead of his actual tail, he didn’t lose any blood. 

 Up on the hill, Phil was finishing throwing up bile. He stood, shakier than ever, and turned, looking down the hill to where Dan lay in a heap, covered in grass and out of the water, but still very much alive.

**Author's Note:**

> This work was written as part of the 12 Days of Prompts on my writing Tumblr account. Find the rest of the 12 Days of Prompts [here](https://dansphlevels.tumblr.com/post/168551853918/12-days-of-prompts-masterpost). I also did a painting for this fic, which you can find [here](https://dansphlevels.tumblr.com/post/168614421728/mermaids-please-i-love-mermaids). 
> 
> Check out my tumblr dedicated purely to writing phanfiction [here](https://dansphlevels.tumblr.com/). You can also request a phanfic [here](https://dansphlevels.tumblr.com/ask). Please comment and tell me what you think!


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